A farm vehicle tyre has a tread having a toroidal base surface extending about a central axis of rotation; and a number of lugs extend radially upwards from the base surface, and each have a front wall and a rear wall with respect to a given rolling direction.
Normally, the leading and trailing edges of the section of each lug with respect to a plane perpendicular to the axis of rotation are linear and converge outwards, so that each lug has a trapezoidal section with respect to a plane perpendicular to the axis of rotation.
To improve traction of a farm vehicle tyre on muddy terrain, Patent Application JP-7032820-A proposes a farm vehicle tyre in which the leading edge of the section of each lug in a plane perpendicular to the axis of rotation is a cycloid.
To improve traction of a farm vehicle tyre on muddy terrain, Patent Application EP-0903249-A1 proposes a farm vehicle tyre in which the leading edge of the section of each lug in a plane perpendicular to the axis of rotation comprises a curved bottom portion and a straight top portion.